Pistachio nuts, once harvested, must be processed and dried in a very short period of time in order to preserve freshness and to derive an end result of nuts with desirable organoleptic properties to potential consumers. The drying process for pistachio nuts varies greatly with the type of equipment used, which may range from sun-drying methods to batch drying nuts when subject to heated air. One type of apparatus for drying nuts and grains with heated air is a device that is referenced as a continuous feed vertical dryer, which utilizes large forced-air heaters that push dry air through the dryer device to achieve a desired moisture level of the material being dried. Such dryer devices are typically used for drying gains such as field corn, and are often utilized for drying nuts, including pistachio nuts, without significant modification with concern for specific properties or needs for pistachio nuts being dried and processes. Also, such dryer devices typically have a large internal capacity for drying sizable volume of material in a batch, usually filled in a continuous fill operation in which the entire dryer inner chamber must be filled before it is operational for drying. This construction and fill operation is depicted in FIG. 4A herein. If such a device were only partially filled, the heated air would move through open, unfilled regions of the device, rather than passing through the seeds/nuts packed in the device, resulting in inefficient drying unless the device is completely filled. In this manner, the typical dryer assemblies used for continuous feed vertical drying of seeds and the like are not suitable for drying pistachio nuts, and there is a need for improvements.
Also, typically, continuous feed vertical dryers are constructed of sheet stock, such as joined pieces of perforated metal sheets, are joined together such that small spaces and joint-seams are exposed as the material passes down through the dryer. This results in the material, or debris associated with the material (such as small twigs mixed with pistachio nuts being dried), being sometimes caught within the spaces/seams and causing a back-up that disrupts flow and/or causes a risk of fire. Finally, typical prior art dryer assemblies are constructed in a ways that mike it difficult to clean or repair the assembly or parts. For example, typical prior art dryers are equaled with bottom rollers that assist with control of the flow of nuts through the dryer. Such rollers, usually constructed of a single elongated paddle style roller, are inserted as a single length of roller seated in wooden yokes. This construction has the disadvantage of being difficult to service in the event the roller breaks or a supporting yoke needs replacing. Typically, such repair is done by removing the roller from the entire apparatus, which requires much time and multiple workers to complete.
There are numerous other deficiencies relating to typical dryer assemblies in relation to drying pistachio nuts. These include difficulties with controlling the flow rate of nuts being introduced into and migrating through the dryer, as well as lack of a way to put out a fire if one occurs in the dryer, resulting in significant financial loss due to damage of a dryer full of nuts. Thus, there is a need for improved structure and processes for drying pistachio nuts. The present invention solves these and other deficiencies that exist with the typical dryer assemblies.